Most often, a ski has a rectangular cross-section, the lower surface of which is delimited by the sliding sole, the upper surface of which is delimited by a serigraphed covering wall, and the two lateral faces of which are delimited by sides. At the junction line between the sole and the sides, metal edges are arranged, which make it possible to improve the guiding conditions and the holding on hard snow and on ice.
It is also known to produce skis, the sides of which are not perpendicular to the lower surface and to the upper surface, but inclined so as to form, over at least a part of the length of the ski, an acute angle with the lower sole. At the ends of the ski--tip and heel--this angle can have a value which is lower than that which is found in the area of the runner. Such an arrangement makes it possible to permit skiing in powdery snow, since the ends of the ski "cut through" the snow better than in the case of a ski which is of rectangular cross-section over its entire length.
Seen in transverse cross-section, skis with inclined sides generally have inclined rectilinear parts, possibly concave or convex, in the area of the sides.
The object of the present invention is to provide a ski with inclined sides, in which the profiles of the inclined zones of the sides, which are constituted by curved convex or concave lines, have a variable curvature along the ski.
Such a structure makes it possible to influence the mechanical characteristics of the ski, its esthetic quality and the resistance to wear of the upper edges.
However, skis with inclined sides present production difficulties. A ski with inclined sides can be obtained directly by molding in a shaped mold. In such a case, it is appropriate to have available equipment which is costly and difficult to implement for certain structures.
It is also conceivable to produce a ski with inclined sides by machining the sides with the aid of a numerically controlled machine tool. However, in order to produce special shapes, and in particular curved surfaces, it is appropriate to have available a fourspindle machine, with a cylindrical milling cutter, which requires a major investment. It would also be possible to carry out machining with the aid of a machine tool with three spindles, with a shaped milling cutter.